Tuesday, July 16, 2019

Pink Quartz, not Rose Quartz in Harford County, Maryland

The question is whether the above pictured image is actually rose quartz. This writer collected it in Southeastern Harford County, Maryland. Rose quartz has never  been officially identified and verified as occurring in Maryland. 

Numerous well-versed regional authorities who viewed this specimen have given different reasons why they believe it is not rose quartz. While most of them were credible, none were scientific. “You could call it rose quartz" was as close as any response came to a confirmation of rose quartz. However, it went on to note: "It's just not quite the right color.” 

The genuine rose quartz specimen  at left was placed amidst a varied  assortment of quartz cobbles and pebbles that members of a family collected in the woods behind their house. On a recent visit, the specimen in our title picture turned up after we had spent about 15 minutes turning over rocks in their woods. It visually resembled the uncontested rose quartz specimen as much as any of the previously collected pieces shown at right. 

The locality is a wooded area to the southwest of Rt. 152 about 2 1/2 miles northwest of I-95. It is at a point where Maryland's Coastal Plain intersects with its Piedmont. Small cobbles of quartz and quartzite  along with a few less distinctive metamorphic rocks are ubiquitous underfoot. Nearly all of the quartz and quartzite show color: red, yellow orange, brown, and ---yes pink. These colors result from a presence of iron oxide, typically hematite, that has stained the quartz and has often become included within as the quartz formed millions of years ago from a complex sequence of geological events. 

By the standard definition, rose quartz owes its color to inclusions of crystals of one, possibly other minerals within the quartz. Staining is never a factor. The inclusions are separate, miniscule and all but impossible to separate so that  analysis of them by x-ray diffraction is rarely possible.

Mindat cites two studies stating that massive rose quartz always has a "hazy to translucent character due to microscopic fibrous inclusions of a pink borosilicate mineral related to dumortierite." The likelihood is all but nil that inclusions of such a species, which is not known to occur in Maryland, would show up within quartz pebbles exclusively in an area where most of the quartz shows iron oxide staining and/or inclusions. Without analysis or a nearby presence of verified rose quartz, a better option is to call the material “pink quartz.” 

It takes a good polish, has more variants, and can be just as pretty.

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